/* 
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System;

namespace Lucene.Net.Index
{
    
    
    class SegmentTermVector : ITermFreqVector
    {
        private System.String field;
        private System.String[] terms;
        private int[] termFreqs;
        
        internal SegmentTermVector(System.String field, System.String[] terms, int[] termFreqs)
        {
            this.field = field;
            this.terms = terms;
            this.termFreqs = termFreqs;
        }

        /// <summary> </summary>
        /// <value> The number of the field this vector is associated with </value>
        public virtual string Field
        {
            get { return field; }
        }

        public override System.String ToString()
        {
            System.Text.StringBuilder sb = new System.Text.StringBuilder();
            sb.Append('{');
            sb.Append(field).Append(": ");
            if (terms != null)
            {
                for (int i = 0; i < terms.Length; i++)
                {
                    if (i > 0)
                        sb.Append(", ");
                    sb.Append(terms[i]).Append('/').Append(termFreqs[i]);
                }
            }
            sb.Append('}');
            
            return sb.ToString();
        }

        public virtual int Size
        {
            get { return terms == null ? 0 : terms.Length; }
        }

        public virtual System.String[] GetTerms()
        {
            return terms;
        }
        
        public virtual int[] GetTermFrequencies()
        {
            return termFreqs;
        }
        
        public virtual int IndexOf(System.String termText)
        {
            if (terms == null)
                return - 1;
            int res = System.Array.BinarySearch(terms, termText, System.StringComparer.Ordinal);
            return res >= 0?res:- 1;
        }
        
        public virtual int[] IndexesOf(System.String[] termNumbers, int start, int len)
        {
            // TODO: there must be a more efficient way of doing this.
            //       At least, we could advance the lower bound of the terms array
            //       as we find valid indexes. Also, it might be possible to leverage
            //       this even more by starting in the middle of the termNumbers array
            //       and thus dividing the terms array maybe in half with each found index.
            int[] res = new int[len];
            
            for (int i = 0; i < len; i++)
            {
                res[i] = IndexOf(termNumbers[start + i]);
            }
            return res;
        }
    }
}